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Патент USA US2404700

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Patented July 23, 1946
William John Roy Evans, Blaclgley, ‘Manchester,
England, assignor to Imperial Chemical Indus
tries Limited, a corporation of Great Britain .
No Drawing. Application January 2, 1945,, Serial‘
No. 571,121. ’ In Great Britain November 25,
4 Claims.
(01. 260-.—34_5)
This invention relates to improvements in the
Preferably, an antioxidant, for example, di
manufacture of vinyl ethers, more particularly
phenyl-p-phenylenediamine,ris included with the
to improvements in the manufacture of vinyl
ethers from actylene and alcohols.
In a convenient way of operating the process
It is known that vinyl ethers may be obtained UK of the?invention the alkoxide dissolved in some
by reacting acetylene and alcohols in the pres
of the alcohol which is to be converted into the
ence of basic substances which act as catalysts
ether is added to a large proportion of the sec
during the reaction, for example, potassium
ondary or tertiary amine. The mixture, is heated
However, such processes usually re
quire the use of high pressures and are accom
panied by the hazards necessarily associated with
in a reaction vessel for example, at 1504-180‘? C.
the use of acetylene athigh pressures.
It has been proposed to make vinyl ethers from
acetylene and, alcohols at ordinary pressuresby
interacting them in the presence of basic sub
stances, for example, potassium alkoxides, and
under conditions such that the presence of oxygen
is avoided, as by passing a stream ‘of an inert
gassuch as nitrogen through the liquid. Acety
lene gas and the alcohol in vapour form are then
passed through the liquid, for example, at a
pressure of 2-5 lbs. per square inch, the liquid
preferably being maintained at about ITO-190° C.
in~the presence of liquids, for example liquid
The issuing vapours are, fractionated and con
para?in, which boil at temperatures higher than
densed, and the ether, which‘is in the con
the reaction temperature. Although working‘ in
densate, is collected, and, ‘ii desired, puri?ed by
accordance’ with this proposal obviates the 20 conventional means.
hazards involved in using acetylene at high pres
The invention is illustratedbut not limited by
sures, experiments show that. under such condi
the following examples, in which the parts are
tions, the life of the catalyst is short.
expressed by weight.
It has now been found that, when vinyl ethers
Example 1
are made by reacting acetylene and alcohols at 25
ordinary pressures with a potassium alkoxide as
5.5 ‘parts of potassium are dissolved in 32 parts
the catalyst, the use of secondary or tertiary
of isobutyl alcohol and 38 parts of ethylaniline
aromatic amines as high boiling media for the
in presence of 1.1 parts of diphenyl-p-phéhyl
reaction greatly lengthens the life of the catalyst
and also appreciably enhances its activity.
Thus, according to the present invention there
enediamine. This solution is transferred to a
reaction tower, which is ‘?ttedwith a fractionat
ing column with dephlegmator control‘ and a
ethers excluding the n-butyl ether, the prepara
means of condensing vapours’which pass through
the column, containing 1155 parts of dried ethyl
tion of which by this same process is the subject
of Serial No. 562,736, ?led‘ November 9, 1944, I
aniline at a temperature of 160° C. through which
a stream of dry nitrogen is passing.
which comprises bringing acetylene and an alco
hol ‘into contact with a potassium alkoxide dis
The medium is then heated at 178-1829 C‘. and
the nitrogen ?ow reduced gradually to zero whilst
a mixture of acetylene at'35 parts per hour and
isobutyl alcohol at 160 parts per hour, preheted
to l80-190° C. is fed at a pressure just greater
than atmospheric into the base of the tower
through a gas distributor. ‘A mixture of vinyl
is provided a process for the manufacture of vinyl
solved or suspended in a medium consistingsolely
or mainly of a secondary or tertiary aromatic
amine at a pressure not substantially greater
than atmospheric and-at a temperature of about
150-250" C.
As alcohols which may be used in the produc
tion of vinyl ethers in accordance with the proc
ess of this invention there may be mentioned
methyl, ethyl, propyl, isopropyl, isobutyl, tert
butyl and tetrahydrofurfuryl alcohols.
As secondary or tertiary aromatic amines there
may be used, ‘for example, methylaniline, di
methylaniline, ethylaniline, diethylaniline, di
ethyl-o- and p-toluidines, benzylaniline, diben
zyline and benzylethylaniline.
isobutyl ether, isobutyl alcohol and acetylene
passes from‘ the top of the tower to the base of
a iractionating column. The isobutyl alcohol
returns to the reaction tower while the azeotropic
mixture of vinyl isobutyl ether and ‘isobutyl alco
hol passes out of the head of ‘the column and‘ is
condensed and collected. The ether is puri?ed
50 by distilling over sodium, and amaterialof ex
cellent purity is obtained. The production- of
ether initially is 90 parts per hour‘ ‘and, 'falls
As catalysts it is preferred to use the potas
gradually to 30 parts per hour after 13 hours.
sium alkoxide prepared from the alcohol which
A total of 849 parts of the vinyl isobutyl ether is
is to be converted into the ether.
55 obtained during 13 hours.
The spent catalyst separates from solution; it
Example 4 _
may be withdrawn from the bottom of the tower
and replaced with fresh catalyst solution, thus
enabling the process to be operated continuously.
Example 2
A 5-litre ?ask is ?tted with a high speed (2000
Working in a stirred vessel as in Example 1,
potassium ethoxide in diethylaniline is used to
catalyse addition of ethyl alcohol (industrial ab
solute alcohol dried by azeotropic distillation with
benzene) to acetylene. The reaction proceeds at
160~l65°, and a column headtemperature of 37°
R. P. M.) centrifugal gas-dispersing stirrer, be
to 44° is maintained by adjusting the alcohol feed
low which is a jet through which nitrogen or
rate. Vinyl ethyl ether of 60% strength or higher
acetylene and alcohol vapour can be fed. 2 litres 10 is obtained according to the control exercised,
of diethylaniline are put into the ?ask, which is
and may be puri?ed by fractional distillation,
then closed and ?tted with a short stripping col
washing with water, and drying.
umn to re?ux diethylaniline from the ellluent
Example 5
The ?ask is surrounded by an elec
trically heated jacket and the contents are heated
Vinyl methyl ether can be obtained from methyl
to 160-170° C. while passing nitrogenthrough
alcohol by a process similar to the foregoing.
to displace air and dry the diethylaniline.
Benzylethylaniline is a suitable amine and with
Catalyst solution, comprising 7.8 gm. of potas
this a reaction temperature of 280—250 is used.
sium dissolved in '70 gm. of isobutyl alcohol, ‘1.0
The ether has a low boiling point and the receiver
gm. of diphenyl-p-phenylenediamine and 50 gm. 20 must be suitably cooled.
ofdiethylaniline is then added under nitrogen.
The excess of isobutyl alcohol, which distils all
is removed at the foot of the stripping column.
‘The temperature is then raised to 185-190° C. and
I claim:
1. A process for the production of vinyl ethers
which comprises passing acetylene and an alco
hol taken from the group consisting‘of ‘methyl,
‘kept there with the nitrogen shut off, while acet 25 ethyl, propyl, isopropyl, isobutyl, tertiary butyl,
and tetrahydrofurfuryl alcohols into a liquid re;
'ratelthat the column head temperature is be
action medium taken from the group consisting
tween 65-75°'C. Vinyl isobutyl ether of 90-98%
of secondary and tertiary aromatic aminesvcon
‘strength distils oiT, and is condensed and col
taining the potassium alkoxide corresponding; to
lected. The rate ‘of production is initially about
the alcohol passed into the compositionQat, a
‘ylene and isobutyl ‘alcohol are fed in, at such a
94 gm./hr., and is still 86 gm./hr. after 9 hr.,
the equivalent of ‘724 gm. of 100% pure vinyl
isobutyl ether having then been obtained. The
temperature of 150° C. to 200° C.
- i
2. A process for the production of vinyl ethers
which comprises passing, in the vapor phase, acet
experiment is then discontinued. Next day on
and an alcohol taken from the group con
restarting similarly," adding further catalyst made 35 ylene
sisting of methyl, ethyLpropyl, isopropyl, iso
from 8.4 gm, potassium, production proceeds at
butyl, tertiarybutyl, and tetrahydrofurfuryl alco
~115-120 gm./hr. and continues with product de
hols into a liquid reaction medium taken from the
‘crease to 74 gm./hr.,- during whichtime 2060 gm.
group consisting of secondary and tertiaryaro
matic amines containing the potassium alkoxide
is obtained from 16.2 g. potassium i. e. 1'70 gm. 40 corresponding to the alcohol passed into the com
per‘g‘m. of potassium, and the catalyst is still
position, at a temperature of 150° C. to 200° C‘. _.
3. A process for the production of vinyl ethers
Example 3 a
which comprises passing, in the vapor phase, acet
of ether are obtained. Thus a total of 2784 gm.
1490 gm. of diethylaniline are put into a 5-litre
ylene and an alcohol taken from the group, con
?ask and dried by passing dry nitrogen through 45 sisting of methyl, ethyl, propyl, isopropyl,,iso
butyl, tertiary butyl, and tetrahydrofur’fu'ryl alco
at 160° C. 5.5 gm. of potassium are dissolved in
hols, together with diphenyl-p-phenylenediamine
31.5 gm. of tetrahydrofurfuryl alcohol and 50 gm.
of diethylaniline under nitrogen, and the hot
as an antioxidant, into a liquid reaction medium
taken from the group consisting of secondary and
solution is transferred to the 5-litre ?askin ab
sence of air and moisture. The mixture is then 50 tertiary aromatic amines containing the potas
.heated to 180—190°, C., while dry acetylene and
dry tetrahydrofurfuryl alcohol are passed through
with vigorous agitation. The reaction vessel is
?tted with a short stripping column, which re
sium alkoxide corresponding to the alcohol passed
into the composition, at a temperature of 150° C.
4. A process for the productionof vinyl ‘ethers
turns diethylaniline but passes on the alcohol and I
which comprises passing nitrogen through a com
acetylene excess, together with the vinyl tetra
hydrofurfuryl ether formed. Tetrahydrofurfuryl
alcohol is then fed at such a rate that the column
position comprising an alcohol‘ taken. from the
group consisting of methyl, ethyl, propyl, iso
propyl, isobutyl, tertiary butyl, and tetrahydro
head temperature is about 146° C., and acetylene
furfuryl alcohols, a potassium alkoxide corre
is fed at about 0.4 cu. ft./hr., and the crude 00 sponding to the alcohol present in the composi
ether/alcohol mixture is removed continuously.
tion, and a liquid reaction mediumtaken' from
Fractionation of the product followed by distilla
tion over sodium yields practically pure vinyl
tetrahydrofurfuryl ether, B. P, 161-162°/759 mm.
the group consisting of secondary and, tertiary
Treatment of 100 parts of a sample of the ether
with 1- part of stannic chloride dissolved in 8
parts of petrol results in almost instantaneous
polymerisation to a viscous syrup.
complex at minus 40° C.,gives a colourless tacky 70.
180° C., then passinga mixture of acetylene and
the said alcohol, in the vapor phase, through said
rznixture at a temperature between 150° C‘. and
Treatment'with boron tri?uoride/acetic acid
-. solid polymer.
aromatic amines, at a temperature of 150° C. to
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